1. Field of the Invention
Embodiments of the invention relate to a temperature “Indicator”. More particularly, the present inventions and various embodiments disclosed herein pertain to, for example, an embodiment of a novel Indicator comprised of a novel indicator strip containing thermochromic liquid crystal; and the thermochromic liquid crystal in the indicator strip indicates when a predetermined temperature has been reached by changing to a certain or predetermined color (the “novel Indicator strip” or “novel Indicator structure”). Another embodiment of the present inventions pertain to a novel indicator having a novel indicator housing used in conjunction with either a prior art Indicator Strip or in conjunction with the novel Indicator Strip/Structure. Embodiments containing one of or both a novel Indicator strip/structure and a novel Indicator housing will hereinafter be referred to as a novel Indicator.
2. Discussion of the Related Art
The present inventions relate to temperature monitoring of perishable, or temperature sensitive products, or objects for which temperature is important to its function (collectively “temperature sensitive product” or “Product”) in which the useful life of that Product is dependent upon a function of its cumulative exposure to a particular stimulus, such as temperature, over a period of time through the use of Indicators. Although such Indicators may be used in multiple scenarios, from forehead thermometers to fish tank thermometers, for purposes of illustration only, the detailed disclosure in this application will focus on the use the Indicators in conjunction with Objects that should, for example, be used to ensure the safe shipment and/or storage of the temperature sensitive product (the “Object”). And more particularly, this application will use as an example of the Object a panel filled with Phase Change Material (“PCM”), wherein the Indicator is used in conjunction with PCM-filled panels (i.e., the indicator is used to monitor these Objects and indicate when they reach a predetermined temperature or temperature range) so as to ensure that the Product being shipped is packed for shipment within its proper temperature range.
By way of example only, many types of temperature sensitive products, such as pharmaceuticals (and more specifically vaccines), must be maintained within a temperature safe zone of between 2° C. and 8° C. from the time of manufacture until they are used. If such Objects are exposed to temperatures that are either below or above their respective safe zone, the Products can spoil and/or become inert.
Therefore, it is important to insulate such Products by maintaining them in a temperature-constant environment when they are being shipped or stored. To aid in shipping the Products in a temperature constant environment that protects that Product from harmful temperature excursions, an entire industry has arisen around the manufacture and use of a “cooler system.” These cooler systems employ a box (typically manufactured using corrugated and/or insulated walls), wherein the box contains removable hollow panels that aid in the insulation of the box. These hollow panels are typically made of highly durable plastic, and are filled with an insulating material. Preferably, the insulating material used is a Phase Change Material (or “PCM”), which as its name implies, changes phases as it moves through various temperature ranges. These phases include a solid when the PCM is frozen, ½ frozen and ½ liquid when melting, and is a liquid when all the PCM warms past its melt point.
A cooler system is typically a box made up of any number of PCM-filled panels. For example, the cooler system can include six PCM-filled panels that are arranged in the shape of a cube. The PCM has several different operating temperatures, but for the sake of illustration herein, the PCM-filled panels are pre-conditioned to a temperature of −20° C. prior to their use. Once pre-conditioned, the PCM-filled panel is removed from the freezer unit and is placed in a warmer environment so that it can thaw to its “Packing Temperature Range” or “PTR”. The Packing Temperature Range is the temperature range at which the cooler system is assembled, and is also the temperature range at which the Product being shipped can be safely inserted into the cooler system. For example, when a cooler system or box is packed with six PCM-filled panels, it can maintain the 2° C. and 8° C. temperature (by way of example only, the temperature necessary for the shipment of vaccines) for possibly as long as ninety six hours. To have a cooler system that employs PCM-filled panels maintain that 2° C. to 8° C. temperature inside the cooler system for the length of time it takes to transport the Product, the manufacturers of the PCM-filled panels recommend that the cooler system be assembled, and the temperature sensitive product be placed inside assembled cooler system, when the temperature of the PCM-filled panels is between, by way of example only, 2° C. and 5° C. Thus, the Packing Temperature Range for assembling the six PCM-filled panels into the cooler system, and for inserting the exemplary vaccine Product into the cooler system for shipment, is between 2° C. and 5° C.
As discussed above, the use of PCM as a part of the cooler system enables the cooler system to better maintain a constant temperature environment inside the assembled cooler system for an extended period of time, thereby better protecting the Product being shipped inside the assembled cooler system from exposure to harmful temperatures. There are a couple of challenges, however, associated with the use of PCM-filled panels in the cooler system as it pertains to determining when the PCM-filled panels have reached their Packing Temperature Range. By way of example only, one such problem is that the user who is shipping the temperature sensitive product (such as vaccine) typically employs an electronic infra-red temperature sensing device (the “IR gun”) to scan the surface of the PCM-filled panel so as to obtain the surface temperature of the PCM-filled panel.
Not surprisingly, there are several problems associated with using an IR gun to determine the surface temperature of the PCM-filled panels. First, the surface temperature is impacted by the temperature of the ambient air touching the PCM-filled panel, and therefore the IR gun more closely reports the temperature of the room where the PCM-filled panel is thawing in conjunction with the temperature of the PCM, rather than reporting the temperature of the core of the PCM-filled panel. Second, the PCM inside a PCM-filled panel will begin melting at the surface of the PCM that touches the interior side of the PCM-filled panel, and then the melting of the PCM will move toward the interior of the PCM-filled panel. The problem this melting feature creates as it pertains to the packing of the cooler system, is that the very thin layer of melted PCM that touches the interior of the PCM-filled panel might be within the targeted Packing Temperature Range of between 2° C. and 5° C., but the majority of the PCM inside the PCM-filled panel can still be at a much colder temperature (such as anywhere between −20° C. to 0° C.). Essentially, the IR gun is unable to measure the core temperature of the PCM-filled panel.
This pertains to another problem associated with the use of PCM-filled panels, specifically that the PCM-filled panel may not be completely filled with PCM. In such a situation, if the PCM-filled panel is frozen horizontally with Side A up, the “dead air” or “head space” will be collected at the top of Side A in the interior of the PCM-filled panel. Similarly, if the PCM-filled panel is defrosted with Side A up, the air in the dead space will reach the warmer targeted packing temperature (for example, 3° C.) faster than the rest of the PCM in the PCM-filled panel. Consequently, when the person packing the cooler system uses the IR gun to determine the temperature of the PCM-filled panel, that IR gun will mistakenly determine that the PCM-filled panel is within the Packing Temperature Range, when it is in fact much colder.
Alternatively, if the panel is frozen with Side A up but is then defrosted with Side A facing down (i.e., with Side B facing up), the PCM will be touching the interior wall of Side B of the PCM-filled panel. Because this inside wall of Side B will cause the PCM touching it to melt faster than the PCM at the interior of the PCM-filled panel, when the user employs the IR gun to determine the temperature of the PCM-filled panels, she will still reach an inaccurate reading of the temperature of those PCM-filled panels as described above.
These issues associated with the use of the IR gun to determine the true temperature of a thawing PCM-filled panel results in the following problematic situation: i) if the cooler system is assembled at the point in time when the surface of the PCM-filled panels is registering between 2° C. and 5° C.; ii) but the interior of the PCM-filled panels is actually −4° C.; iii) the assembly of the six PCM-filled panels into a cooler system will result in the thermal energy of those PCM-filled panels super-cooling the interior of the cooler system down to about −4° C. (the “Super Cooling Effect”). The consequence of the Super Cooling Effect is that the temperature sensitive product being shipped inside the cooler system (such as vaccine) will be exposed to that −4° C. temperature, causing the Product to freeze (and most likely be rendered ineffective). Thus, there is a need for an Indicator that can better determine the actual temperature of the PCM-filled panel(s), and more particularly can better determine the actual temperature of the interior of the PCM-filled panel(s), and thereby avoid the problems associated with assembling a cooler system containing the six PCM-filled panels at an improper temperature (e.g., prevent the PCM-filled panels from super-freezing (or as explained herein, prevent the problems associated with “super-thawing”) the Product being shipped or stored).
A problem with the prior art Indicator strip is that the currently available thermochromic liquid crystal formulations provide a very quick response to the temperature to which the prior art Indicator strip is exposed. Although such a fast-response device may work well when monitoring certain Objects in certain situations, in other instances this quick response time is actually detrimental. For example, when the prior art Indicator is used to monitor the temperature of PCM-filled panels, the formulation of the prior art thermochromic liquid crystal is too sensitive to the influences of ambient temperatures.
More specifically, as shown in FIG. 1A, FIG. 1B and FIG. 1C, the prior art Indicator strips are typically placed on a side of the Object being monitored (which in this instance is a PCM-filled panel 100). Because the prior art Indicator 120 is typically placed on the same side of the Object 100 that is impacted by the ambient air circulating around the Object 100 (and by default impacting the prior art Indicator 120 strip), and because the temperature of the ambient air is very different from the temperature of both the prior art Indicator strip 120 and the Object 100, the temperature reading of the prior art Indicator 120 strip is negatively impacted by that ambient air, because the ambient air negatively effects the accuracy of the prior art Indicator strip 120.
For example, if a PCM-filled panel 100 that had a prior art Indicator strip 120 attached to its top surface 105, was defrosting on a lab table from its pretreatment temperature of −20° C., and the room temperature was at 21° C., that panel would slowly warm to its Packing Temperature Range of 2° C. to 5° C. in about twenty minutes. However, if a fan was nearby the lab table and was moving air across the PCM-filled panel 100 and the prior art Indicator 120, the fan would cause the prior art Indicator strip 120 to indicate a colder temperature than the actual temperature of the PCM-filled panel 100. This combination of the multiple temperatures (the core temperature of the PCM-filled pane 100, the temperature of the ambient air, and the temperature of the air moving across the prior art Indicator strip 120, will cause the prior art Indicator strip 120 to display an inaccurate temperature indication to the user that is monitoring the temperature of the PCM-filled panel 100, because the prior art Indicator strip will likely indicate that the temperature of the Object 100 is colder than it actually is (but the indication could be warmer that it actually is depending on the temperature of the ambient air). Other instances of ambient temperature negatively impacting the operation of the prior art Indicator can arise simply from a person walking past the thawing PCM-filled panel 100 to which the Indicator strip 120 is attached; or from a person touching the prior art Indicator strip 120 (and thereby imprinting the person's thermal signature onto the prior art Indicator strip 120).
All these examples of ambient temperature negatively impacting the operation of the prior art Indicator all lead to the same result as described above—an inaccurate temperature indication generated by the prior art Indicator, which leads to the user assembling the cooler system too soon, and super-cooling the temperature sensitive product (such as vaccine) being shipped. Thus, there is a need for an improved Indicator with a housing that better insulates the Indicator strip from the negative ambient influences arising from airflow and physical touching.
Another problem with the prior art Indicators is that the operation of the device is dependent on the speed at which the thermochromic liquid crystals contained inside the Indicator “operate”. Specifically, thermochromic liquid crystals operate by changing color in response to changes in the temperature impacting the thermochromic liquid crystals. This response (i.e., the color change) occurs because the spacing between the thermochromic liquid crystal molecules changes therefore changing the wavelength of the light reflected to the observer.
The problem associated with the operation of the thermochromic liquid crystal as it pertains to its responsiveness to temperature is that the thermochromic liquid crystals are “too responsive” to the temperatures to which they are exposed. For example, if a slight breeze is created by a nearby fan, or is created by someone walking past the prior art Indicator, and that breeze is a temperature different than that of the Object to which the prior art Indicator is attached and is monitoring the temperature of, that breeze results in the prior art Indicator improperly indicating a temperature that is different than the one that should be indicated (i.e., the temperature of the Object being monitored by the prior art Indicator).
The responsiveness or speed at which the color of the prior art Indicator strip changes, is directly correlated to the speed at which the thermochromic liquid crystals change their orientation in response to a change in temperature. This change in orientation is simply a function of the way in which the thermochromic liquid crystals operate. Unfortunately, that quick responsiveness leads to the Indicator indicating a temperature different from the temperature of the Object being monitored; which could lead to the user assembling the cooler system at the wrong point in time (and ultimately super-cooling or super-thawing the temperature sensitive product being shipped in the cooler system). Thus, there is a need for an Indicator strip containing a thermochromic liquid crystal formulation that includes a component that slows down the responsiveness of the thermochromic liquid crystals reacting to a change in temperature.
Another problem with the prior art Indicators is that the liquid crystal formulations employed in the operation of the prior art Indicator have a wide range of operation when compared to its color change. For example, assuming a thermochromic liquid crystal is formulated to begin changing color (has a “Red Start”) at 2° C. and complete its color change at 11° C., the following should occur. First, when the thermochromic liquid crystal contained in the prior art Indicator is below 0° C., the prior art Indicator strip will appear black (assuming the color of the backing layer facing the user is colored black) because no color is being reflected off the thermochromic liquid crystal to the user.
Depending on the formulation of the thermochromic liquid crystal inside the prior art Indicator, as the liquid crystal warms to about 2.0° C., the liquid crystal reaches its Red Start and will turn a reddish color. Then as the temperature of the thermochromic liquid crystal inside the prior art Indicator strip continues to warm, and approaches about 3.0° C., the thermochromic liquid crystals continue to change their spacing and start to reflect a green color to the user. Thus, the “Color Range” of the red color in this example is about one degree Celsius (i.e., from about 2.0° C. to about 3.0° C. but it could reach 3.5° C.). Then as the thermochromic liquid crystals continue to warm and change their orientation, at about 4.0° C. they start to reflect a blue color to the user. Thus, the Color Range of the green color in this example is about one degree Celsius (i.e., from about 3.0° C. to about 4.0° C., but it start at 3.5° C. and could reach 4.5° C. or even 5.0° C.). One of ordinary skill in the art will recognize that the combination of the Color Range for the red color plus the Color Range for the green color is known as the “Color Play” or “Width”. It is also understood by one of ordinary skill in the art that the thermochromic liquid crystal formulation can be formulated so that the Color Range for red color can either be equal to, or not be equal to, the Color Range of the green color.
Similarly, as the thermochromic liquid crystals continue to warm and change their orientation, at about 7.5° C. they start to reflect a purple color to the user. Thus, the Color Range of the blue color in this example is about three and one-half degrees Celsius (i.e., from about 4.0° C. to about 7.5° C., but could start at about 5.0° C. and last until about 8.5° C.). Finally, as the thermochromic liquid crystals continue to warm and change their orientation, at about 11.0° C. they start to reflect no color to the user (because at that point the user is viewing the back layer of the strip). Thus, the Color Range of the purple color in this example is about three and one-half degrees Celsius (i.e., from about 7.5° C. to about 11.0° C., but it might not start until 8.5° C. and last until about 12.0° C.). The combination of all the Color Ranges (i.e., the about 1 degree Celsius for red+the about 1 degree Celsius for green+the 3.5 degrees Celsius for blue+the about 3.5 degrees Celsius for purple) equals a “Color Display Range” of nine degrees Celsius.
The Color Range of the blue color can be much longer than either the Color Range of the red color or the green color (partially because the early blue color will still contain some green color). In fact, the Color Range of blue might be three or more times as long as the Color Range for either the red color or the green color reflected by the thermochromic liquid crystals to the user. The same can be true for the Color Range for the purple color as it corresponds to the Color Range of the red color and/or the green color. It is not uncommon for one of ordinary skill in the art to not even refer to the purple color reflected by the thermochromic liquid crystals, and instead when one of ordinary skill in the art refers to a blue color, she or he will be referring to the combination of the blue color and the purple color. However, because the inventions described herein pertain to colors and shades of color, this application will occasionally distinguish between the blue and purple colors reflected by the thermochromic liquid crystals to the user of the prior art Indicator strips.
The problem with the prior art Indicator strips is that the color visible at the higher end of the thermochromic liquid crystals' Color Display Range, which is the blue Temperature Range and/or the purple Color Range, persists for longer than the proportional range of the lower temperatures (e.g., the Color Range for a red color and/or the Color Range for a green color), especially given the long blue Color Range as it slowly changes from a green color, and slowly changes to a purple color, before all color reflection ends. By way of example only, if thermochromic liquid crystal is formulated so that the Color Play for the red color and the green color equals two degrees Celsius (i.e., one degree Celsius for red, plus one degree Celsius for green), when that prior art Indicator strip moves from green to blue, the Color Range for the blue color will last for at least three and one-half degrees Celsius or more. Moreover, the Color Range for the purple color that follows the blue color will also last for at least three and one-half degrees Celsius or more.
In certain applications, these long lasting Color Ranges for the blue and purple colors may be so confusing to the user that the Indicator is of no use because the Color Display Range of that Indicator is too wide for a given use. By way of example only, if the Indicator is needed to indicate a Color Display Range that is just three degrees Celsius wide (by way of example only, the three degrees Celsius range of the Packing Temperature Range for vaccine), such an Indicator would be impossible to manufacture with the current technology because although the Color Play of the red color and the green color would equal about two degrees Celsius, because of the operation of the thermochromic liquid crystal, the Color Range of the blue and purple colors would last at least three and one-half degrees Celsius each. Consequently, the Color Display Range for that Indicator would be at least nine degrees Celsius (e.g., (about one degree Celsius Color Range for red)+(about one degree Celsius Color Range for green)+(about three and one-half degrees Celsius Color Range for blue)+(about three and one-half degrees Celsius Color Range for purple)=a Color Display Range of nine degrees Celsius)) rather than the desired Color Display Range of three degrees Celsius.
These long persisting blue and purple Color Ranges are problematic for at least two reasons. First, thermochromic liquid crystals can only be formulated for a temperature resolution of about 0.5° C. Thus the narrowest a Color Range for a red or green color can be is point-five degrees Celsius. And thus the Color Range for its corresponding blue and purple colors would be about three-point-five times the Color Range of red or green, or a Color Range of one-point-five degrees Celsius for blue and a Color Range of one-point-five degrees Celsius for purple. (Thus, it may be impossible to manufacture an Indicator that possesses a Color Display Range of only two degrees Celsius, because the red Color Range plus the green Color Range would require a combined total of one-point-zero degree Celsius, and the blue Color Range and the purple Color Range would require one-point-five degree Celsius each; which equals a Color Display Range of four-point-zero degrees Celsius (e.g., (one-half degree Celsius for red)+(one-half degree Celsius for green)+(one and one-half degrees Celsius for blue)+(one and one-half degrees Celsius for purple)=a total of four degrees Celsius)) rather than the desired two degrees Celsius Color Display Range. Thus, there is a need for an Indicator that is able to at least partially block (or possibly completely block) a given color's Color Range from being reflected to the user of the Indicator so as to obtain an Indicator with a reduced Color Display Range.
It should be appreciated that this long Color Range associated with the blue color, and the long Color Range associated with the purple color creates another problem for the use of the prior art Indicator in conjunction with the PCM-filled panels (as well as for other applications). Specifically, because of the long Color Range of the blue color and the long Color Range of the purple color, the user could be misled into thinking that the PCM-filled panels were within the desired Packing Temperature Range (by way of example only, 2° C. to 5° C.) because a color indication (in the form of a blue color or purple color) was still visible in the Indicator. But in fact, because the corresponding temperature of that blue color was 6° C. or 7° C. (and thus, outside the desired Packing Temperature Range) the temperature of the PCM material in the panel had already thawed and warmed to such a point that there was not enough thermal energy left in each panel to protect the Product being shipped in the cooler system.
For example, if the prior art Indicator was showing a purple color, the user responsible for packing and shipping the temperature sensitive product might understand that purple color to mean that the PCM-filled panels were within the proper Packing Temperature Range for assembly and shipment. In reality, the purple color is an indication that the PCM had already melted to the point where the temperature of the PCM was 7° C. or higher. At that point, the cooling system containing the assembled six PCM-filled panels would not have enough cooling energy left in the panels to protect the temperature sensitive product being shipped in the cooling system from prolonged exposure to hot temperatures (known as “Super Thawing”). Consequently, that temperature sensitive product would be rendered ineffective by an exposure to an excursion to a warm temperature. Thus, there is a need for an Indicator that possesses a way for the Color Display Range displayed to the user to be narrowed.
This inability of the prior art Indicators to indicate temperatures in a narrow Color Display Range (by way of example only 3.0° C. or less) results in the next problem associated with these prior art Indicators, which is that in order to accurately indicate an Object was within a desired Color Display Range of just 3.0° C., the user must: i) employ an Indicator with at least two distinct sections that each provide its own color indication (i.e., the “Display Panels”); ii) each Display Panel must contain its own distinct thermochromic liquid crystal formulation; and iii) the user must compare the color of a first Display Panel to the color of a second Display Panel, and make a cognitive decision regarding the supposed temperature of the Object based on the differing colors displayed by the two formulations in their respective Display Panels. As will be explained below, this prior art Indicator can be very confusing for the user.
Referring to FIG. 1C and FIG. 1D, the prior art Indicator strip 120 requires the use of a first collection of thermochromic liquid crystals 125 contained in a first display panel 126 having its own formulation, so as to provide a color change at a first temperature, and requires the use of a second collection of thermochromic liquid crystals 125 in a second display panel 127 also having its own formulation different from that of the thermochromic liquid crystal 125 contained in the first display panel 126, so as to provide a notable color difference between the first display panel 126 and the second display panel 127. The liquid crystal formulations in each of the first panel 125 and the second panel 126 differ in their Red Start temperature. In the prior art Indicator strip 120, the Red Start temperature for the liquid crystal formulation in the first display panel 126 is lower than the Red Start temperature of the liquid crystal formulation in the second display panel 127. The difference between the Red Start temperature for the thermochromic liquid crystals in the first display panel 126 and the thermochromic liquid crystals in the second display panel 127 is by way of example only about two to three degrees Celsius.
The prior art Indicator strip 120 in FIG. 1D also includes small orientation squares 129 that are colored a certain color so as to contrast with the color of the first display panel 126 and the color of the second display panel 127. The template 128 is used to visually separate the first display panel 126 from the second display panel 127 of the Prior Art Indicator strip 120 in their activated state. The orientation squares 129 are located on top of the prior art Indicator strip 120 and are used by the end user to verify the orientation of the prior art Indicator strip 120, because without the orientation squares, the user would likely not know which of the display panels 125 and 126 would be formulated to be the first Red Start color change.
As described herein, thermochromic liquid crystals can reflect different colors as they are heated or cooled. Below the Red Start temperature, a liquid crystal strip will appear black due to the backing layer being colored black. However, as the Indicator strip is heated above the Red Start temperature, the film will first appear red, then green, then blue, and then purple until finally the Indicator strip becomes black again. Given that the prior art Indicator 120 strip in FIG. 1D contains a first display panel 126 and a second display panel 127, and each display panel can display several colors (black, red, green, blue and purple), there are several possible color combinations that can be displayed by the prior art Indicator 120 depending on the temperature the prior art Indicator strip 120 is exposed to.
As described herein, the prior art Indicator strip 120 can be attached to an Object so as to be used to determine the temperature of that Object. When the Object to which the prior art Indicator strip 120 is attached is colder than the Red Start temperature of the liquid crystal formulations 125 contained in both the first display panel 126 and second display panel 127 of the prior art Indicator strip 120, both display panels 126 and 127 will appear black (as shown in FIG. 1D by the hash marks). Thus, if an Object were thawing from a freezing temperature to a warmer temperature, the black color of the display panels 126 and 127 would indicate to a user that the Object is at a temperature that is lower than the Red Start temperature of the liquid crystal formulations in the first display panel 126 and second display panel 127 and thus is not within the Packing Temperature Range. Note that the color of the template 128 (that provides shape and detail to the prior art Indicator) is also black; and therefore, when the temperature of the Object is colder than the Red Start temperatures of the first display panel 126 and the second display panel 127, no contrast is evident.
The Red Start temperature of the liquid crystal 125 formulation in the first display panel 126 coincides with a temperature of interest to the end user. The Red Start temperature of the liquid crystal 125 formulation in the second display panel 127 coincides with a second temperature of interest to the end user. In general, the end user is interested in determining whether the temperature of the Object 100 is supposedly within the Packing Temperature Range, which would be between the Red Start temperatures of the first display panel 126 and the second display panel 127.
The prior art Indicator strip 120 is designed in such a way that when it is attached to an Object that has been frozen, several color combinations are observed when the Object thaws to a warmer temperature. For instance, as the temperature of the thawing Object rises beyond the start-of-indication temperature of the first display panel 126 but is still lower than the start-of-indication temperature of the second display panel 127, several color combinations are possible as shown in FIG. 1E. The first combination to appear as the temperature rises is shown by the prior art indicator strip 130 in FIG. 1Ea, which shows the first display panel 136 appearing red (as denoted by the dots) and the second display panel 137 appearing black (as indicated by the hash marks). Note that the color of the template 138 is black and therefore good contrast is evident between the red color of the first display panel 136 and the template 138.
The second combination to appear as the temperature rises is shown by the prior art Indicator 140 depicted in FIG. 1E, which shows the first display panel 146 appearing green (as denoted by the unfilled circles) and the second display panel 147 appearing dark (as indicated by the hash marks). Note that the color of the template 148 is black and therefore good contrast is evident between the green color of the first display panel 146 and the template 148.
The third combination to appear as the temperature of the Object rises is shown by the prior art Indicator 150 in FIG. 1Ec which shows the first display panel 156 appearing blue (as denoted by the diamond-shaped marks) and the second display panel 157 appearing black (as indicated by the hash marks); which supposedly indicates that the Object is within the desired Packing Temperature Range. Note that the color of the template 158 is black and therefore good contrast is evident between the blue color of the first display panel 156 and the template 158.
The three color combinations displayed collectively in FIG. 1Ea through and including FIG. 1Ec show that the temperature of the Object is within the Packing Temperature Range and is demarcated by the Red Start temperatures of the first display panel 136, 146 and 156, when compared to the color of the second display panel 137, 147 and 157, respectively. As such, the PCM-filled panels or Objects could be at the proper temperature for assembling the cooler system and shipping the temperature sensitive product, supposedly without concern that: i) the assembled cooler system would Super Cool the temperature sensitive product being shipped; or ii) the assembled cooler would lack enough thermal energy to protect the Product being shipped against Super Thawing.
Although the operation of the prior art Indicator as described collectively in FIG. 1Ea through and including FIG. 1Ec is initially desirable because it appears that only a single display panel 136, 146 and 156 would be needed to alert the user that the temperature of the Object was within the Temperature Packing Range, as described above, the Color Display Range over which liquid crystal films effectuate their change of Color Range from black to red, green, blue, purple and black again is so wide, it requires at least two display panels 126 and 127 to be used. This shortcoming of thermochromic liquid crystal becomes obvious when the user desires to monitor the temperature over a Color Display Range that is a very short (by way of example only, a Color Display Range of three degrees Celsius). Therefore, if an Indicator of the type described in FIG. 1Ea through and including FIG. 1Ec is desired that has a Packing Temperature Range of three degrees Celsius, because of the long persistence of the blue and purple colors through their Color Range, the prior art Indicator 130 requires the use of the at least two panels to allow the user to discern whether the temperature of the Object was still within the Packing Temperature Range.
This is why, as shown in FIG. 1Ec, when the Object to which the Indicator is attached is thawing, a color combination is possible in which the first display panel 156 turns blue and/or purple while the second display panel 157 remains black or dark.
However, due to the persistence of the blue and purple colors over a wide temperature range, the start-of-indication temperature of the second formulation of the liquid crystal 125 included in the second display panel 157 is set to coincide with the highest temperature in the temperature range of interest to the user. Therefore, as the temperature of the thawing Object continues to rise, several other color combinations are possible as shown by FIG. 1F so as to warn the user that the temperature of the Object (e.g., the PCM-filled panel) had exceeded the Packing Temperature Range.
For instance, the first color combination encountered as the temperature rises beyond the Packing Temperature Range and causes the Red Start temperature of the second display panel 167 to be visible, is shown by the prior art Indicator 160 in FIG. 1Fa, which shows the first display panel 166 showing a blue color (as indicated by the diamond-shaped marks) and the second display panel 167 showing a red color (as shown by the dots). Note that the second display panel 167 also contains the message “NO!” to advise the user that even though a color is observed in the first display panel 166 and in the second display panel 167, the temperature of the Object being monitored is higher than the Packing Temperature Range. Because the color of the “NO!” message is black, it blends in with the black color of the second display panel when it has not yet reached a temperature that causes the thermochromic liquid crystals to reflect a color (as shown in 137, 147 and 157), and therefore the user cannot view that NO! message until the liquid crystal 125 contained in the second panel 137 or 167 reaches its Red Start temperature. Note that the color of the template 168 is also black, and therefore as shown in FIG. 1Fa, good contrast is evident between the blue color of the first display panel 166, the red color of the second display panel 167 and the black color of the template 168.
The second color combination encountered by the user as the temperature of the Object rises above a desirable Packing Temperature Range, is shown by the prior art Indicator 170 in FIG. 1Fb, which shows the first panel 176 showing a black color (as indicated by the hash marks) and the second display panel 177 showing a green color (as shown by the unfilled circles). Note that the second display panel 177 contains the message “NO!” to advise the user that even though a color is observed in the prior art Indicator 170, the temperature is higher than the Packing Temperature Range. Note that the color of the mask 178 is black and therefore good contrast is evident between the green color of the second display panel 177 and the template 178.
The third color combination encountered as the temperature rises beyond the desirable Packing Temperature Range, which is evidence by the Red Start of the second display panel 187 being visible, is shown by the prior art Indicator 180 in FIG. 1Fc, which shows the first display panel 186 showing a black color (as indicated by the hash marks) and the second display panel 187 showing a blue or purple color (as shown by the diamond-shaped marks). Note that the second display panel 187 contains the message “NO!” to advise the user that even though a color is observed, the temperature of the Object being monitored is higher than the temperature range of interest. Note that the color of the template 188 is black and therefore good contrast is evident between the blue color of the second display panel 187 and the template 188.
A reprint of the user instructions for the interpretation of the two panel prior art Indicator 120, 130, 140, 150, 160, 170 and 180 is shown in FIG. 1G, along with the instructions to possibly understand its operation.
What should be appreciated by the fact it took multiple paragraphs to describe how prior art Indicators 120, 130, 140, 150, 160, 170 and 180 function, is that the device is very cumbersome and difficult to use when determining whether or not the temperature of the Object is within the Packing Temperature Range, as evidenced by the confusing user instructions at FIG. 1G. Moreover, because a first display panel 136 and a second display panel 137 are necessary in order for the user to be able to discern whether or not the Object is within the Packing Temperature Range, by default at least a first formulation and a second formulation are required for the first display panel 136 and the second display panel 137, respectively, to convey the confusing message to the user (i.e., the Object was or was not within the desired Packing Temperature Range).
It should also be appreciated that each formulation in each of the two display panels 136 and 137 has a cost associated with manufacturing the formulation, applying the formulation to the cardboard, etc. Thus, by way of example only, it is desirable that an Indicator for certain embodiments have just a single display panel so as to: i) eliminate the need to perform the cognitive steps associated with the use of multiple display panels so as to determine when the Object is within its Packing Temperature Range; ii) eliminate the need for orientation boxes so as to be able to determine which is the first display panel and which is the second display panel; iii). eliminate the confusion associated with the use of multiple display panels; and iv) reduce the cost associated with use of multiple display panels.
It should also be appreciated that there are other prior art Indicators that employ not just two, but three display panels in order to display to the user whether the Object being monitored is within the Packing Temperature Range. In very simple terms and as shown in FIG. 1H, the three display panel prior art Indicator 190 has a first panel 196 containing an “X” to indicate, when it is visible, that the temperature of the Object to which the three display panel prior art Indicator 190 is attached is at too low of a temperature for the cooling system to be assembled and the Product packed into the cooling system. The second display panel 197 contains a “√” to indicate, when it is visible, that the Object is at the desired temperature (i.e., the PCM-filled panel is within the Packing Temperature Range for assembly into the cooling system). And the third display panel 198 contains an “X” to indicate, when it is visible, that the temperature of the Object (likely the PCM-filled panel) is too high for the cooling system to be assembled and the Product being inserted into the assembled cooler system.
As with the two-panel prior art Indicator discussed above in regard to FIG. 1D, FIG. 1E and FIG. 1F, each of the formulations in the three display panels 196, 197 and 198 are designed to interact with each other, so as to provide a message to the user as to whether or not the Object was within its Packing Temperature Range. Thus, the three-panel prior art Indicator 190 has the same problems as the two-panel Indicator. By way of example only, one problem with the three panel prior art Indicator 190 is the fact that it contains three display panels 196, 197 and 198, and each display panel contains a separate liquid crystal formulation which has all the problems discussed herein. Moreover, the user of the three panel prior art Indicator 190 must perform cognitive thinking and comparisons of the glyphs 199 displayed in the three display panels 196, 197 and 198 to properly determine whether the Object whose temperature is being monitored (e.g., a PCM-filled panel) is at the proper temperature for assembly into the cooling system (i.e., within the Packing Temperature Range). Thus, it would be advantageous to have a thermochromic liquid crystal Indicator that contains a single display panel, because such an Indicator would be easier for the user to employ, and would be less expensive to manufacture.